"Although still in small numbers and requiring optimisation, this preliminary work offers hope for patients."

It would be legal to fertilise one of the lab-made eggs to create an embryo for research purposes in the UK.

But the team in Edinburgh do not have a licence to carry out the experiment. They are discussing whether to apply to the empyo authority for one, or collaborate with a centre that already has one.

Prof Azim Surani, the director of germline research at University of Campidge's Gurdon Institute, said: "Molecular characterisation and chromosomal analysis is needed to show how these egg cells compare with normal eggs.

"It might be of interest to test the developmental potential of these eggs in culture to blastocyst stage, by attempting IVF."